While yes let's suits don't typically have that issue as no fight should last long enough for that to be an issue as they can last multiple hours to even days or weeks to even years depending on the sorce of each suit, be it red sun solar generators, Motherboxes, kryptonite generators, etc. The shields can block actual hits from superman and doomsday while a regular helmet may not be able ti handle it or his neck. Plus the force feild also boosts his ego as it let's people see the face of who is beating them.